April, ’18] McCOLLOCH: FALSE WIREWORMS ELEODES 221 
cocoons in which they pupate. In spinning these cocoons the soil is 
webbed together, making it difficult to find them. In the rearing 
work, the larvae would not construct cocoons unless there was soil 
present. The length of the pupal stage was determined for several 
hundred parasites and was found to range from 8 to 15 days, with an 
average of 9 days. 
On emerging, the adults are rather active but make little effort to 
fly. On placing the parasites in cages containing adult beetles, they 
were found remaining close to the ground and apparently trying to get 
under the beetles. Shortly after introducing parasites into the cages, 
the beetles became frantic in their movements, running in every direc¬ 
tion. The parasites could be observed clinging to the legs of the beetles 
and were apparently trying to oviposit in the abdominal sutures and at 
the junction of the legs and body. The parasites did not appear to 
mind being run over and carried around by the beetles but seemed 
intent on gaining hold on the ventral side of the abdomen. 
Actual oviposition was not definitely observed and, owing to the 
chitinous integument of the beetle, it was impossible to dissect them 
and find the eggs. For this reason the length of the egg stage wsis not 
determined. The length of the egg and larval stages combined aver¬ 
aged about 12 days, with extremes of 10 and 18 days. 
Large numbers of parasites may infest a single beetle, and as high 
as 124 larvae were secured from an individual. The average number of 
parasites bred from a beetle was about 50. It is interesting to note 
that the beetles live from 12 to 48 hours after the larvae leave the body 
and maintain most of their normal activities up to the time the parasites 
leave. One female deposited three eggs the same morning that she 
yielded 124 Periiitus larvae. 
The efficiency of this parasite in the field was not definitely estab¬ 
lished. In 1916, as high as 50 per cent of the beetles collected in 
August were parasitized, but, from the data at hand, it would seem that 
the average parasitism is only about 5 or 7 per cent. Of the 932 beetles 
collected in 1917, not a single one was parasitized. 
Physiological Relations 
Effect of Humidity. —Most of the species of the genus Eleodes are 
confined to the semi-arid regions of the United States west of the 
Mississippi River. They reach their greatest abundance, both in 
species and individuals, in those areas of little rainfall. As has been 
stated elsewhere in this paper, only three species have been authen¬ 
tically recorded east of Kansas. Owing to the wide distribution of 
E. tricostata, however, it is probably not as greatly influenced by mois¬ 
ture conditions as most of the species. 
5 
